The invention relates to a support assembly for an ink-jet printing device as it is described in claim 1.
A method for producing a support of this kind as well as such a support have been known from the EP 2 000 316 A1 of the same applicant. In this case, the walls of the support are formed by combining top belt modules, bottom belt modules, front wall modules and rear wall modules that are assembled one after another in the longitudinal direction of the support. In the interior of the support, transverse webs are provided, spaced at distances apart from one another. Furthermore, at least one guide track is provided on the support extending in its longitudinal direction for a unit mounted so that it can move along the guide track. In order to obtain a high precision of the guide tracks, the latter are formed by machining regions of the modules to remove material after the modules and transverse webs have been assembled. Though it was possible to improve the guiding precision between the print head carriage and the support, a satisfying constant distance between the nozzle outlets and the surface of the object to print on could not be achieved.
The underlying objective of the present invention is to create a support assembly for guiding a print head carriage of a ink-jet printing device, which has a compact design and during the printing process allows a nearly constant distance across the entire longitudinal extension of the support assembly between the mostly planar surface of the object to print on and the frontal end of the print head with the nozzles arranged there.
This objective of the invention is achieved by features according to claim 1. The advantage gained as a result of the features in claim 1 resides in the fact that the possibility is created to deform the additional supporting element with respect to the supporter in such a way that the latter is orientated in its mostly horizontal position, in a straight-lined way and thus without deflection under load, also in the event of being stressed by the unit, such as the print head carriage, that can travel along the guide track. Due to the fact that the support element at its two ends is supported in a load-bearing way with respect to the support, the desired pre-stress with respect to one another can be such increased by means of the adjusting element that the rectilinearity can be maintained across the entire longitudinal extension of the supporter, also in the event of highest stress. Thus, a parallel guiding with respect to the printing table or the object to print on lying thereon can be maintained also with larger distances between the bearing places of the supporter. Due to the nearly or complete elimination of the sagging of the supporter where the print head carriage is guided at, a constant distance between the nozzles dispensing the fluid printing medium and the surface of the object to print on is maintained across the entire adjustment way of the print head carriage. As a result, a proper print quality of the printed image produced by the inkjet-printing device is achieved.
Also of advantage is another embodiment according to claim 2, because thereby a cross-section of a support is created, which itself already provides a certain rigidity, in particular in case of rectangular embodied hollow bodies. Similarly, a perfect longitudinal guide along the guide track can also be achieved.
Also of advantage is an embodiment according to claim 3, because thereby an adjustment to different operational conditions for guiding the print head carriage can easily be created.
Due to the embodiment according to claim 4 it is possible to detect the existing deflection under load and the thereto related deviation from the rectilinearity of the support. Due to the corresponding pre-adjustment or the adjustment of the adjusting elements, the extent of the pre-tensioning with respect to one another between the support and the supporting element can be adjusted and set.
According to another variant of embodiment according to claim 5 it is possible to quickly react automatically to different deflections under load and to compensate the latter thereby as quickly as possible. Additionally, possibly appearing vibrations of the support assembly by modifying the mutual pre-tensioning between support and supporting element can also be decreased or compensated thereby.
Also of advantage is an embodiment according to claim 6, because a statically relatively stiff support having a low self-weight at a high stability against deflection under load is thereby also created.
In case of an embodiment according to claim 7 it is of advantage that across nearly the entire longitudinal extension of the support, an compensation of the deflection under load or the sagging can take place. Furthermore, also the supporting power can be transferred from the supporting element, directly via the support to the machine frame of the inkjet-printing device and no additional bending load of the support across its longitudinal extension results.
Due to the further embodiment according to claim 8 it is achieved that a sufficient deformation between the support and the supporting element is allowed, with the result that also a higher extent of deflection under load of the support can be compensated.
Due to the embodiment according to claim 9, a vertical tensioning of support and supporting element respective to one another can be achieved and thus, the deflection under load caused by the influence of the self-weight or the weight of the print head carriage can be counteracted.
Also of advantage is an embodiment according to claim 10, because thus the most compact dimensions for the support will be sufficient. Additionally, the possibility is created to accordingly retrofit existing supports without requiring additional alteration works in the region of the guide tracks.
Finally, also an embodiment according to claim 11 is possible, because thus, the most diverse operating conditions can easily be considered and the most advantageous respective adjusting element can be provided for different users.
The invention will be explained in more detail below with reference to examples of embodiments illustrated in the appended drawings.